.add-button{
    position: fixed;
    bottom: 58px;
    width: 40px;
    right: 30px;
    height: 40px;
    border-radius: 50%;
    z-index: 999;
    background-color: rgba(25,137,250,.50);
}
.van-back-top{
    background-color: rgba(25,137,250,.50);
}